Intersections

The version of this function taking Point arguments finds the
intersection points, if any, of the
Reg_Cl_Plane_Curve and the line
p
that passes through the Points
p_0
and
p_1.
In the other version, the Path argument must be a linear
Path, and its first and last Points are passed to the
first version of this function as p0 and p1, respectively.

Let
C
be the Reg_Cl_Plane_Curve.
C and p can intersect at at most two intersection points
i_1 and i_2.
Let bpp be the return
value of this function.
The intersection points need not be on the line segment
between pt0 and pt1.
bpp.first.pt will be set
to the first intersection point if it exists, or INVALID_POINT if
it doesn't. If the first intersection point exists and is on the line
segment between pt0 and pt1

In [next figure]
, the line AB
is normal to the
Ellipse e, or, to put it another way, AB
is
perpendicular to the plane of e. The intersection point i_0 lies
within the perimeter of e.

The line DE
is skew to the plane of e, and
intersects e at i_1, on the perimeter of e.